Currently, mobile devices such as a smart phone, a tablet personal computer (PC), and the like, are distributed and use thereof is also gradually expanded. Accordingly, use of wireless-fidelity (Wi-Fi) using a non-license band is significantly increasing. In the case of Internet traffic, a half of the Internet traffic depends on Wi-Fi. Therefore, interference between Wi-Fi devices connected to adjacent different access points (APs), that is, belonging to different basic service sets (BSSs) is increasing day by day. In particular, in 802.11ac of which standardization is currently in progress, bands at 20 MHz, 40 MHz, 80 MHz, and 160 MHz, which are relatively wide frequency bands compared to 802.11n using bands only at 20 MHz and 40 MHz, are determined to be available and thus, the probability of using a partially overlapping or a completely overlapping channel between adjacent APs is further increasing. Accordingly, to efficiently use frequency resources, solving interference between overlapping basic service sets (OBSSs) becomes an important issue.
To solve an interference issue between OBSSs found in the existing 802.11 standard technology, the Institute of Electrical and Electronics Engineers (IEEE) 802 standardization group proposes an OBSS management method in 802.11aa of which standardization was completed in May of 2012 and an 802.11ac amendment standard in progress. The OBSS management method discloses a method of providing information for selecting an operation channel between an AP and a neighboring AP through OBSS management, an access control mechanism, a method of sharing a channel between OBSSs based on the scheduled concept of transmission opportunity (TXOP), and the like. The TXOP is based on a hybrid coordination function (HCF) controlled channel access (HCCA) protocol that is an HCF non-contention channel access scheme. The HCCA protocol integrally manages transmission of each of stations (STAs) at an AP using a non-contention based channel access scheme using a polling mechanism.
An OBSS interference avoidance method based on the HCCA protocol causes inconvenience in that since transmission between all of the STAs is integrally managed at an AP, a large amount of information required for this needs to be exchanged between adjacent APs. There is an issue in that interference avoidance and resource allocation through scheduling at the AP causes significant overhead in the entire network.